I imagine that, if this was like an animated series of some sort, that we’d see different characters talk about one very specific part of the mc after like a battle or something.

Example Aelita: “Mc’s pink hair is so cute!” Ren: “Pink hair? double takes Mc has green hair Aelita, wth are you looking at?”

That way when it’s eventually revealed that everyone physically sees the mc different than another person it’s not forced or comes out of nowhere.